Recently, a rapid thermal processing (RTP) method is widely used as a method of heat treatment for substrate and the like.
The rapid thermal processing method is a method of heating up processing for substrate by illuminating radiation beam out of heat source like tungsten lamp onto substrate. Such a rapid thermal processing method has a merit that it can heat up or cool down a substrate more rapidly than a conventional method of heat treatment for a substrate using a furnace, and it can improve the quality of heat treatment for a substrate with easy adjustment control for pressure condition or temperature band.
A conventional substrate processing apparatus with which a rapid thermal processing method is used comprises a chamber providing a space in which a substrate is processed; a susceptor supporting the substrate in the chamber; and a heat source unit illuminating radiation beam to heat up the substrate. Here, the heat source unit may comprise a heating block for installation of a heat source and may be arranged along inside of the chamber.
Therefore, energy consumption is inevitable with a need for a heat source of higher output to process a substrate since not only the size of the chamber itself but also the distance between the heat source and the substrate is increased for securing an installation space of the heat source unit.
And as the substrate becomes of large area, the volume of a substrate processing apparatus for processing the substrate becomes increased rapidly. Usually a substrate is loaded into the chamber in horizontal direction and accordingly the size of the chamber in which the substrate is processed becomes increased. Therefore, there is a problem that price competitiveness falls owing to increased facilities cost with relatively wider space required for installation of the substrate processing apparatus and storage of the substrate of large area. And there is another problem that a uniform processing for overall substrate is difficult since a phenomenon occurs in which a substrate hangs downward owing to self weight of the substrate in case where a substrate of large area is loaded in horizontal direction.
On the other hand, graphene is a conductive substance with thickness of single layer of atom in which carbon atoms make an array of honeycomb shape in two-dimension and has been an important model for study of diverse nano phenomenon in low level. And the grapheme is a very excellent conductor as well as a very stable substance in structural and chemical sense, and is predicted as it can move an electron about 100 times more swiftly than silicon does and it can make about 100 times of electrons flow than copper does.
The grapheme has a merit that it can be processed very easily to single-dimensional or two-dimensional nano-pattern since it is made of only carbon which is a relatively light element. Especially in case that this merit is utilized, not only semiconductor-conductor characteristics can be adjusted, but also production of functional device of wide scope such as sensor, memory and the like becomes possible using diversity of chemical defect which carbon has.
However, a practical mass synthesis method for grapheme has not been introduced yet which is applicable to a real commercial use despite the excel lent electrical, mechanical and chemical merit that the grapheme has as stated above. Conventionally, a method is mainly known in which grapheme is mechanically ground and dispersed in a solution, and then is fabricated as a thin film using a self-assembly phenomenon. In this case, though there is a merit of low cost, it does not reach to the expectation of electrical and mechanical characteristics, since it is made as a structure in which numerous grapheme pieces are connected with overlapping one another. And there is a case in which a grapheme thin film is known as possible to be fabricated having conductivity similar to that of metal with introduction of a synthesizing technology of graphene of large area by chemical vapor deposition method introduced recently. However, there is also a problem that this also requires high cost and relatively high process temperature. Therefore, an effort is required for developing a synthesizing technology of grapheme of large area using the rapid thermal processing method which can provide the process temperature required in graphene synthesis.